From the Guidelines
The relapse rate for T1a HER2-positive breast cancer is approximately 8.7% over a 10-year period, based on the 10-year invasive DFS of 91.3% reported in the NCCN clinical practice guidelines in oncology 1. This type of breast cancer is characterized by a tumor size of 0.1-0.5 cm with human epidermal growth factor receptor 2 (HER2) overexpression. Despite the small tumor size, HER2-positive status increases recurrence risk compared to HER2-negative tumors of similar size. Standard treatment typically includes surgical removal (lumpectomy or mastectomy), followed by radiation therapy if breast-conserving surgery was performed. For T1a HER2-positive tumors, adjuvant systemic therapy with HER2-targeted agents like trastuzumab (Herceptin), often combined with chemotherapy, may be recommended depending on individual risk factors. Some key points to consider in the management of T1a HER2-positive breast cancer include:
- The use of paclitaxel and trastuzumab as a less intensive therapeutic option, preferred for patients with low-risk T1,N0,M0, HER2-positive disease, particularly those not eligible for other standard adjuvant regimens due to comorbidities 1.
- The relatively low relapse rate reflects improvements in targeted therapies, but individual risk can vary based on specific tumor characteristics and treatment adherence.
- Regular follow-up with clinical exams every 3-6 months for the first three years, then every 6-12 months for two years, and annual mammograms are essential for monitoring. The decision for adjuvant therapy should consider other prognostic factors such as hormone receptor status, tumor grade, patient age, and overall health. The long-term follow-up data reported 10-year invasive DFS of 91.3%, breast cancer-specific survival of 98.8% and OS rates of 94.3% for patients with small, node-negative, HER2-positive tumors treated with paclitaxel and trastuzumab 1.
From the Research
Relapse Rate of T1a HER2+ Breast Cancer
- The relapse rate of T1a HER2+ breast cancer is not directly stated in the provided studies, but we can look at the relapse rates for similar types of breast cancer.
- A study from 2015 2 found that the 3-year rate of survival free from invasive disease was 98.7% for patients with node-negative, HER2-positive breast cancers, which suggests a low relapse rate.
- Another study from 2019 3 found that the risk of late relapse in HER2-positive breast cancer treated with adjuvant trastuzumab-based chemotherapy is low, particularly in patients with hormone receptor-positive (HR+) disease and no lymph node involvement (N0) or involvement of one to three lymph nodes (N1).
- The study from 2019 3 reported a cumulative hazard for recurrence-free survival of 10.96% for patients with HR+ HER2+ breast cancer during the first 5 years, and a low risk of recurrence in years 5 to 10, with 3.23% in patients with N0 disease and 6.39% in patients with N1 disease.
Factors Affecting Relapse Rate
- The relapse rate of HER2+ breast cancer can be affected by various factors, including the stage of the disease, the presence of lymph node involvement, and the type of adjuvant therapy used.
- A study from 2020 4 found that adding HER2 blockade to adjuvant trastuzumab with pertuzumab and neratinib improves invasive disease-free survival (IDFS), particularly for those at highest risk of recurrence.
- The study from 2019 5 found that combining trastuzumab with chemotherapy lowers death and relapse risks by one-third, but also increases the risk of cardiotoxicity.
Treatment Options
- The treatment options for T1a HER2+ breast cancer include adjuvant trastuzumab-based chemotherapy, which has been shown to improve outcomes in early HER2-positive breast cancer 2, 4.
- A study from 2021 6 found that neoadjuvant T-DM1/pertuzumab and paclitaxel/trastuzumab/pertuzumab are effective treatments for early breast cancer at high risk of recurrence, with predicted pathologic complete response (pCR) rates of 63% and 72%, respectively.